A food scientist studies the reaction between citric acid and sodium hydrogencarbonate solution. The energy levels for the reaction are shown in the table.
| Position in the reaction | Energy (kJ/mol\mathrm{kJ/mol}kJ/mol) |
|---|---|
| Reactants | 75 |
| Highest point | 128 |
| Products | 94 |
A student writes this account of the reaction profile:
“The curve first falls from the reactants level to the products level and then rises to the highest point. The activation energy is 34 kJ/mol, with an arrow from the products level to the highest point. The overall energy change is -19 kJ/mol, with an arrow pointing downwards from the reactants level to the products level.”
Describe how the student's account should be corrected.
106 exam-style questions on OCR GCSE Chemistry 3.2 Energetics, covering 3.2.1 Exothermic and endothermic reactions and reaction profiles and 3.2.2 Calculating energy change from bond energies. Each one has a worked solution and a mark scheme showing where the marks go.